Abstract : A sea floor penetrometer for real-time measurement of sediment shear strength and related geotechnical properties has an accelerometer sensor placed in the nose of a probe to detect deceleration of the probe. The accelerometer sensor is activated just prior to impact and provides data from the moment of impact until the probe comes to rest. The deceleration as a function of time data is transmitted to a deploying platform, amplified and processed through an analog-to-digital (A/D) converter, and stored in the memory of a mini-computer. Computer algorithms are applied to the deceleration data to provide real-time sea floor classification.